Testing inductor with DSO 201 Oscilloscope

[asking]

Hello,

Recently i checked the inbuilt function generator of DSO @ 1KHZ and Frequency shown was normal as it should be. But when i connected inductor in series to the probe. Frequency doubled in the Oscilloscope ? Could anyone tell how that happened ?

I have attached screenshots.

 

[FvM]

It's your secret where you see "Frequency doubled". I only see ringing edges, showing the inductor resonance with oscilloscope input capacitance respectively inductor parallel capacitance. This can be expected.

What are you excatly trying to achieve?

 

[asking]

It's your secret where you see "Frequency doubled". I only see ringing edges, showing the inductor resonance with oscilloscope input capacitance respectively inductor parallel capacitance. This can be expected.

What are you excatly trying to achieve?

Please see the Frequency reading....at top right corner its 1KHZ and after connecting inductor in series to oscilloscope probe..its 2.13KHZ...i just need to know how its frequency measure is doubled ?

 

[schmitt trigger]

"...i just need to know how its frequency measure is doubled ? "

To automatically determine frequency, a scope looks at the period between crossing thresholds.

Look at the green trigger line on IMAGE004...the ringing causes it to cross it twice during each period...thus, without knowing your o'scope in detail, believe is what is going on.

One has to be very careful with automated scope readings. Depending on their settings -which may be adjustable or be fixed presets- it may return false readings. If something does not make sense, double check the reading with cursors, which you can always set visually to the proper position.

 

[asking]

"...i just need to know how its frequency measure is doubled ? "

To automatically determine frequency, a scope looks at the period between crossing thresholds.

Look at the green trigger line on IMAGE004...the ringing causes it to cross it twice during each period...thus, without knowing your o'scope in detail, believe is what is going on.

One has to be very careful with automated scope readings. Depending on their settings -which may be adjustable or be fixed presets- it may return false readings. If something does not make sense, double check the reading with cursors, which you can always set visually to the proper position.

Thanks... for information will keep in mind...next time..